1. Field of the Invention
The present invention relates generally to an auxiliary tire bead depressor, and more particularly, to such a depressor which may selectively depress a tire's upper bead from an upper wheel flange.
2. Description of the Relevant Art
High production tire inflator apparatuses for rapidly inflating tubeless tires wherein sealing between the tires and the wheels occurs at the tire beads are well known. One such typical apparatus is shown and described in U.S. Pat. No. 4,735,250, which is incorporated herein by reference. Most tire inflation machines have an inflation head which depends from a carriage attached to a plurality of rods. The inflation head includes an annular tire seal ring affixed to the lower ends of the rods. A compressed air supply fitting communicates with the seal ring for injecting air within the ring and into the tire. The inflation head of most known machines is designed to have a lower edge of large enough diameter to pass over the largest rim of a wheel to be accommodated by the apparatus. The problem inherent in these machines is that when the machine is used with smaller diameter rims, the lower edge of the inflation head engages the tire at a relatively large spaced distance from the wheel rim. This greatly decreases the volume of the tire, which leads to premature tire bead sealing during inflation and causes lower than specified final inflation pressure in the tire, which is normally 41/2 to 5 bar, or 65 to 75 psi. This problem could be alleviated if the plant air supply could be raised to a high enough pressure. However, plant air supply is normally limited to approximately 6 bar, or 90 psi. In order to raise the plant air supply past this limit, the entire facility would have to be repiped.
Thus, it would be desirable to provide an apparatus which would prevent premature tire bead sealing on smaller diameter tires, yet at the same time would not interfere with the inflation of larger diameter tires. It would also be desirable to provide such an apparatus which could be utilized with already existing inflation apparatus, i.e., an apparatus which can cause an increase in tire inflation pressure while keeping within the limits of the normal plant air supply.